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"We are involved now in a profound failure of imagination. Most of us cannot imagine the wheat beyond the bread, or the farmer beyond the wheat, or the farm beyond the farmer, or the history beyond the farm.

"Most people cannot imagine the forest and the forest economy that produced their houses and furniture and paper; or the landscapes, the streams, and the weather that fill their pitchers and bathtubs and swimming pools with water. Most people appear to assume that when they have paid their money for these things they have entirely met their obligations."
—Wendell Berry

“Researchers trying to replicate the fertility of terra preta have concluded that its secret is in the charcoal. Work by soil scientists like Laird, Johannes Lehmann of Cornell, and Mingxin Guo of Delaware State University suggests that the benefits of supplementing soil with charcoal – which they call ‘biochar’ to distinguish it from the fuel of backyard barbecues – could be dramatic, widespread, and durable.”

“Biochar, they have found, enhances the retention of water and nutrients, decreases the need for fertilizer, encourages microbial growth, and allows more air to reach crop roots. It also breaks down at a far slower rate than traditional fertilizers and soil additives.”

Depending on how the charcoal is made and applied, estimates of its life span range from decades to millennia. Scientists believe that some Amazonian terra preta soils are at least 2,000 years old. ‘Biochar is much more effective at doing all the great things that normal organic matter usually does in soil, but it does it in much more effective ways, and it does it in a much longer way,’ says Lehmann.”
Soil scientists have been experimenting with biochar for just a few years – barely enough time to see how well it performs over repeated plantings. Even its champions concede that there’s plenty we need to learn about how to produce it on a mass scale. Researchers today are looking at how it might best be applied to the soil: in a dust, perhaps, or in pellets, or in a slurry mixed with manure. Two American companies, Eprida and BEST Energies, are working on bringing it to market.